E-Selectin Inhibitor GMI-1271 Works in Combination with Low-Molecular Weight Heparin to Decrease Venous Thrombosis and Bleeding Risk in a Mouse Model

Background: Previous studies have shown that inhibition of E-selectin can decrease thrombus formation and associated inflammation. E-selectin (CD-62E) is a cell adhesion molecule that is expressed on activated endothelial cells and plays an important role in leukocyte recruitment to the site of vascular injury. GMI-1271 is designed to mimic the bioactive conformation of the sialyl-Lex carbohydrate binding domain of E-selectin and is a specific E-selectin inhibitor. There remains an unmet medical need for a translatable therapeutic that can treat VT in combination with lower, safer levels of low molecular weight heparin (LMWH) anticoagulation. We hypothesize that E-selectin inhibition combined with LMWH will permit lower doses of therapeutic LMWH for the treatment of VT without increasing adverse bleeding events.

Methods: Male C57BL/6J mice, 10 weeks old (23-28 grams, n5), underwent our electrolytic IVC model (EIM) to produce a non-occlusive thrombosis, via electrical free radical stimulation (250 µAmp) for 15 minutes. Experimental groups included non-treated controls (CTR-No Tx), animals given LMWH (3-6 mg/kg, SQ, once daily (qd), the E-selectin inhibitor GMI-1271 20/kg intraperitoneal (IP) twice daily (BID), and a combination of the agents. The dose range of LMWH that produced anti-Xa levels in the therapeutic range (0.5-1.0IU/mL) and significantly decreased thrombus weight in this mouse VT model was 5 and 6 mg/kg. Treated mouse groups received the first dose of experimental therapy immediately following thrombus induction and through day 2. Animals were euthanized 2 days post-thrombosis for tissue harvest and blood collection for the following evaluations: thrombus weight (grams), anti-Xa testing, and tail vein bleeding time (seconds).

Results: GMI-1271 Works in Combination with LMWH to Decreases Venous Thrombosis: LMWH dosed at 6mg/kg and 5mg/kg alone, significantly decreased venous thrombus weight at 2 days, versus non-treated controls (73.0±7.5, 62.8±1.9 vs. 186.8±63.9 x10^-4 grams, P<0.01). Notably, the combination of GMI-1271 20 mg/kg + LMWH 4mg/kg (33% dose decrease from LMWH 6 mg/kg), and GMI-1271 20 mg/kg + LMWH 3mg/kg (50% dose decrease from LMWH 6 mg/kg dose), significantly decreased thrombus weight, versus non-treated controls (75.6±17.1, 73.0±14.8 vs. 186.8±63.9 x10-4 grams, P<0.01), equivalent to the results of higher doses of LMWH alone (FIGURE 1 A). GMI-1271 Does not Increase Bleeding Potential: GMI-1271 administration did not significantly elevate tail bleeding times, versus non-treated control mice (67.00±44 vs. 53.8±7.5 seconds). LMWH dosed at 5mg/kg and 6 mg/kg, elevated tail bleeding times in mice with the 5 mg/kg LMWH group significant versus non-treated controls (87±25 vs. 53.8±7.5 seconds, P<0.005). Both animal groups treated with GMI-1271, in combination with lower dose LMWH therapy, had tail bleeding times comparable to non-treated control animals (FIGURE 1 B).

Conclusion: We report, for the first time, that GMI-1271 works in combination with LMWH to significantly reduce acute VT without increasing bleeding times and by inference, bleeding potential. These preliminary studies suggest that E-selectin inhibition with GMI-1271 may be used to treat VT alone, or in combination with lower and safer levels of LMWH anticoagulation.

Figure 1

View largeDownload slide

Figure 1

View largeDownload slide

Close modal